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Gronsfeld Cipher

Polyalphabetic Caesar cipher using a numeric key.

The Gronsfeld cipher is a polyalphabetic cipher made from a series of Caesar shifts. It is similar to the Vigenere cipher, but the key uses digits instead of letters. Don't know the key? Use Solve automatically to crack it from ciphertext.

Enter a keyword, phrase, or alphabet and the rest will be calculated for you.

Sets the language statistics the solver scores against. Choose Auto to detect the plaintext language from the ciphertext and switch to it automatically (needs at least ~20 letters).

Auto-solve assumes the standard A-Z alphabet; results won't match if you've set a custom alphabet.